Process for hardening steel castings.



UNITED STATES PATENT OFFICE.

JOHN W. GEBHARD, OF MUNCIE, INDIANA, ASSIGNOR TO ARMOR STEEL & FOUNDRY COMPANY, OF CHICAGO, ILLINOIS,

A CORPORATION OF ARIZONA TERRITORY.

No Drawing.

Specification of Letters Patent.

Patented Jan. 23, 1912.

Application filed May 15, 1909. Serial No. 496,125.

To all whom it may concern.-

Be it known that l, Joim \V. GEBIIARD, citizen of the United States, residing at, Muncie.in the countyof Delaware and State of Indiana, have invented certain new and useful Improvements in Processes for Har dening Steel Castings, of which the following is a specification. I

This invention relates to improvements in processes for producing a chill, or hardened face on soft steel castings, and the improvements which form the subject-matter of this application constitute a modification of the process described in a pending application for patent filed by me Sept. 21, 1906, under Serial No. 335,535. In the working of the process covered by said application for patent, it has been found that in making castings of large size, the molten steel retains its heat sufiiciently long to effect a perfect fusing of the high-carbon coating composition and the common steel base or body without the aid of either silica or aluminum, hence in producing such castings these elements may be omitted. It has also been found that in producing light castings, valuable results are attained by mixing with the manganese, which is the basis of the coating compound, other elements such as vanadium, ferro-chrome and tungsten either separately or collectively, hence I desire to protect by Letters Patent, the use of these and other elements of a similar nature when combined with manganese or other high carbon metallic products, and a suitable oil or liquid binder which will have a beneficial effect when subjected to the action of the molten metal.

The specific process herein referred to differs from that described in the pending application above mentioned only in the composition applied to the face of the mold, hence I will not repeat in detail the description of the various steps of said process.

The compound or composition consists of finely ground manganese or similar element, containing a relatively large per cent. of carbon, and finely ground ferro-chrome in the proportions of twenty pounds of the manganese to eight ounces of term chrome. These elements are thoroughly mixed together, and when it is desired to apply the mixture to the portions of the mold where the chilled surface is to be produced in the casting, linseed oil is mixed with the powdered elements in sufficient quantities to form a thin paste which is then applied to the face of the mold, forming a coating which covers the indicated portions of the mold to the desired depth. It has been found that the depth of the chill or bardened skin on the casting when produced from a mold thus treated is approximately double the thickness of the coating, so that if a skin one-ei hth of an inch thick is desired on the casting the paste will be applied to a depth of one-sixteenth of an inch.

\Vhile I have found that linseed oil makes the most effective binder for the comminuted metals, I have also used a commercial product known as glutene with fairly good results. I understand that this product is a kind of glue made from fish. Hence I do not wish to be limited to a. vegetable oil as a binder for the metallic elements named, as an animal oil or a glutenous compound or substance may be used in lieu of the oil mentioned.

It should be understood that the oil or other substance used as a binder in this process, has an additional function of generating a high degree of heat when subjected to the molten metal, which facilitates the fusing of the coating compound with the body of the steel mass, and as it gasifies quickly, it-

also aids in carrying off the other gases produced from the molten steel, thus tending to eliminate blisters from the finished product; The quantity of oil used with an admixture of twenty pounds of manganese and .eight ounces 0 ferro-ehrome, is about five ounces.

In producing a castin in a mold coated with the above com oun it has been found that the elements 0 the compound are fused by the molten steel and unitin with the latter produce a hard and dense acing upon the casting at, the points correspondm to the portions of the mold so treated. .lhe texture strength and hardness of this facing depend upon the high carbon properties of the substances used. The fusing is facili tated b the oil which not only forms a binder or the comminuted minerals present, but aids combustion.

Having thus described my invention what,

I claim is 2- 1. In the art of makin paste composed of a fine y ground mange steel castings, a

nese, finely ground chrome and a liquid 1 4. In the art of making steel castings, a binder adapted to be applied to the face of paste composed of finely ground manganese, the mold from which the casting is produced. finely ground chrome and an oil binder in 2. In the art of making steel castings, a substantially the following proportions: 5 paste composed of finely ground manganese, Manganese 20 pounds; chrome 8 ounces; oil

finely ground chrome and an oily binder 5 ounces. adapted to be applied to the face of the mold f In testimony whereof I aflix my signature from which the casting is produced. 1 in the presence of two Witnesses.

3. In the art of making steel castings, a L JOHN W. GEE-HARD. 10 paste composed of finely ground manganese, I \Vitnesses:

and finely ground chrome and a vegetable H. DE Los HIGMAN, oil binder. F. BENJAMIN.

Copies of this patent may he obtained for five cents each, by addressing the Commissioner 01 Patents,

Washington, D. C. 

